1. Field of the Invention
This invention relates to a resonator, and in particular to a resonator for use on an air inlet tube attached to an internal combustion engine.
2. Discussion of the Prior Art
Air is introduced into an automotive engine for creating an air/gasoline mixture which fuels the engine. Typically, the air passes through an air filter, an inlet tube, a throttle body or carburetor and an intake or inlet manifold to the cylinders of the engine. Sound generated in the cylinders, i.e. engine noise travels back through the manifold and the inlet tube.
Many attempts have been made to reduce or attenuate engine noise. Typical devices for sound attenuation are described in for example Canadian Patent No. 703,518, issued to E. Ludlow et al on Feb. 9, 1965, and U.S. Pat. No. 3,111,191, issued to J. Bachert on Nov. 19, 1963; U.S. Pat. No. 3,388,769, issued to R. J. Martoia on Jun. 18, 1968; U.S. Pat. No. 3,612,268, issued to O. E. Rieder on Dec. 1, 1969; U.S. Pat. No. 3,966,015, issued to W. A. Bychinsky on Jun. 29, 1976; U.S. Pat. No. 4,124,092, issued to S. Kajiya et al on Nov. 7, 1978; U.S. Pat. No. 4,132,286, issued to H. Hasui et al on Jan. 2, 1979; U.S. Pat. No. 4,164,266, issued to L. Collin et al on Aug. 14, 1979; U.S. Pat. No. 4,165,798, issued to G. Martinez on Aug. 28, 1979; U.S Pat. No. 4,172,508, issued to L. C. Moss et al on Oct. 30, 1979; U.S. Pat. No. 4,281,742, issued to A. Scheuermann et al on Aug. 4, 1981; U.S. Pat. No. 4,415,059, issued to Y. Hayashi on Nov. 15, 1983; U.S. Pat. No. 4,418,790, issued to R. E. Agnew on Dec. 6, 1983; U.S. Pat. No. 4,538,701, issued to D. C. Lowery et al on Sep. 3, 1985; U.S. Pat. No. 4,574,914, issued to R. T. Flugger on Mar. 11, 1986; U.S. Pat. No. 4,623,035, issued to K. Schad et al on Nov. 18, 1986; U.S. Pat. No. 4,848,513, issued to G. Csaszar on Jul. 18, 1989; U.S. Pat. No. 4,874,062, issued to K. Yanagida et al on Oct. 17, 1989 and U.S. Pat. No. 4,890,691, issued to C. Ching-ho on Jan. 2, 1990.
It is well established that the geometry of a resonator determines the sound attenuating efficiency of the device. In this connection, reference is made to the introductory portion of the Kajiya et al U.S. Pat. No. 4,124,092 which succinctly sets out the physics of the situation. It is readily apparent that the altering of resonator dimensions affects noise attenuation. The mufflers described in the above listed patents, and for that matter mufflers in general are discrete devices which must be installed in an inlet or exhaust system by interrupting the system. Usually the muffler forms part of the system, and is connected to tubes or pipes forming other parts of the system by clamps or welding. Thus, the installation or removal of a muffler is a somewhat difficult, time consuming and often expensive job. Moreover, the structures used to achieve the desired attenuation are often complicated and consequently expensive to produce.